无磷洗涤剂的现状及存在问题

含磷洗涤剂中含的“磷”主要是STPP，作用很大但对环境的危害也很大，它是造成地表水体出现富营养化的重要原因之一，所以许多地方政府都在实行“禁磷”——禁止销售、使用含磷洗涤剂。现在我国使用的无磷洗涤剂中代磷助剂主要有3种，其中4A沸石用量最大，但它会对环境带来新的问题。主要介绍了含磷洗涤剂的危害及无磷洗涤剂的应用现状，指出了我国禁磷后将面临的问题。     

光电双基区晶体管(PDUBAT)的器件模型

本文在考虑了晶体管的小注入效应和大注入效应以及基区宽变效应等因素后,首次用近似和简化的数学表示式和相应的等效电路,描述了光电双基区晶体管(PDUBAT)负阻形成的机理并使负阻区和谷值区的理论计算和实验结果一致性很好.     

酸性盐水及其配套装置的应用与运行

介绍了对进槽盐水由酸碱性改为微酸性的技术改造，减少了副反应的发生，从而提高了电解槽的电流效率。     

The State of the Art in Text Filtering

This paper develops a conceptual framework for text filtering practice and research, and reviews present practice in the field. Text filtering is an information seeking process in which documents are selected from a dynamic text stream to satisfy a relatively stable and specific information need. A model of the information seeking process is introduced and specialized to define text filtering. The historical development of text filtering is then reviewed and case studies of recent work are used to highlight important design characteristics of modern text filtering systems. User modeling techniques drawn from information retrieval, recommender systems, machine learning and other fields are described. The paper concludes with observations on the present state of the art and implications for future research on text filtering. This revised version was published online in July 2006 with corrections to the Cover Date.     

On the Realization of Current－Mode Continuous－Time Operational Transconductance Capacitance Filter

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开关电流技术：一种新的模拟抽样数据处理方法

开关电流（ＳＩ）技术是一种新的模拟抽样数据处理技术，介绍了开关电流电路的基本单元结构，讨论了目前开关电流技术中存在的问题及其解决方法。对开关电流技术与开关电容技术的一些基本特征进行了比较，ＳＩ技术不仅结构简单，而且与标准ＣＭＯＳ工艺兼容，可望替代开关电容电路。     

Effect of processing history on the properties of Ag-based tapes

The Bi-system tapes and coils were prepared by the powder-in-tube method. The effect of processing and heat treatment on the properties of the tapes and coils was studied. It is found that the shearing stress produced by the rolling process may destroy the 2223 phase, and the destroyed 2223 phase cannot be recovered by heat treatment, whereas the pressing stress produced by the uniaxial pressing process only makes the 2223 phase grains break, and the broken 2223 phase can be closed by the heat treatment. TheJ _c values of the rolling samples, pressing sample, and the coil with a diameter of 35 mm are over 1.3×10⁴, 2.5×10⁴, and 4×10³ A/cm² (77 K, 0 T), respectively.     

高频脉冲微束等离子电弧温度场的测试及分析

本文首次采用单波长激光干涉技术，对恒定直流和高频脉冲电流微束等离子电弧温度场进行了测试，并做了分析比较。以电弧温度分布为基础分析了高频脉冲电流微束等离子电弧收缩、稳定的原因。     

Magnetic properties of nickel filament polymer-matrix composites

The magnetic properties of polyethersulfone-matrix composites with 3-19 vol.% polycrystalline nickel filaments (0.4 (im diam) were investigated. These filaments were found to exhibit hysteresis energy loss 10800 J/m³ of nickel and coercive force 16.9 kA/m, compared to corresponding values of 4930 J/m³ and 4.7 kA/m for 2 μ.m diam polycrystalline nickel fibers, 1020 J/m³ and 0.5 kA/m for 20 μm diam polycrystalline nickel fibers, and 1280 J/m³ and 2.3 kA/m for solid polycrystalline nickel.     

High-field magnetic and transport critical current density of Sm-Ba-Cu-O: Agx superconductors at low temperature

Variation of magnetic critical current density (J _mc) and transport critical current density (J _tc) in high magnetic fields at liquid helium temperature were investigated on Sm-Ba-Cu-O: Ag _x (x=0.0, 0.2, 0.4, and 0.6) superconducting samples prepared by the coprecipitation technique.T _c and crystallographic parameters remain unaffected by Ag addition. However, bothJ _mc andJ _tc were found to increase on Ag addition. The volume pinning force (F _p) also increased with increase in Ag concentration, resulting in stronger flux line sheer. Microwave-induced d.c. voltage measurement shows a significant reduction of the total number of weak links between the superconducting grains with increasing concentration of Ag, which creates stronger pinning potentials between the boundary of the superconducting intergrains. Hence, the volume pinning force is greatly enhanced by Ag addition, leading to flux line lattice movement which is responsible for highJ _mc andJ _tc.